/*
 * contrib/pg_trgm/trgm.h
 */
#ifndef __TRGM_H__
#define __TRGM_H__

#include "access/gist.h"
#include "access/itup.h"
#include "storage/buf/bufpage.h"
#include "utils/builtins.h"

/* options */
#define LPADDING 2
#define RPADDING 1
#define KEEPONLYALNUM
/*
 * Caution: IGNORECASE macro means that trigrams are case-insensitive.
 * If this macro is disabled, the ~~* operator must be removed from the
 * operator classes, because we can't handle case-insensitive wildcard search
 * with case-sensitive trigrams.  Failure to do this will result in "cannot
 * handle ~~* with case-sensitive trigrams" errors.
 */
#define IGNORECASE
#define DIVUNION

/* operator strategy numbers */
#define SimilarityStrategyNumber 1
#define DistanceStrategyNumber 2
#define LikeStrategyNumber 3
#define ILikeStrategyNumber 4

typedef char trgm[3];

#define CMPCHAR(a, b) (((a) == (b)) ? 0 : (((a) < (b)) ? -1 : 1))
#define CMPPCHAR(a, b, i) CMPCHAR(*(((const char*)(a)) + i), *(((const char*)(b)) + i))
#define CMPTRGM(a, b) \
    (CMPPCHAR(a, b, 0) ? CMPPCHAR(a, b, 0) : (CMPPCHAR(a, b, 1) ? CMPPCHAR(a, b, 1) : CMPPCHAR(a, b, 2)))

#define CPTRGM(a, b)                               \
    do {                                           \
        *(((char*)(a)) + 0) = *(((char*)(b)) + 0); \
        *(((char*)(a)) + 1) = *(((char*)(b)) + 1); \
        *(((char*)(a)) + 2) = *(((char*)(b)) + 2); \
    } while (0);

uint32 trgm2int(trgm* ptr);

#ifdef KEEPONLYALNUM
#define ISPRINTABLECHAR(a) \
    (isascii(*(unsigned char*)(a)) && (isalnum(*(unsigned char*)(a)) || *(unsigned char*)(a) == ' '))
#else
#define ISPRINTABLECHAR(a) (isascii(*(unsigned char*)(a)) && isprint(*(unsigned char*)(a)))
#endif
#define ISPRINTABLETRGM(t) \
    (ISPRINTABLECHAR(((char*)(t))) && ISPRINTABLECHAR(((char*)(t)) + 1) && ISPRINTABLECHAR(((char*)(t)) + 2))

#define ISESCAPECHAR(x) (*(x) == '\\') /* Wildcard escape character */
#define ISWILDCARDCHAR(x)                    \
    (*(x) == '_' || *(x) == '%') /* Wildcard \
                                  * meta-character */

typedef struct {
    int32 vl_len_; /* varlena header (do not touch directly!) */
    uint8 flag;
    char data[1];
} TRGM;

#define TRGMHDRSIZE (VARHDRSZ + sizeof(uint8))

/* gist */
#define BITBYTE 8
#define SIGLENINT 3 /* >122 => key will toast, so very slow!!! */
#define SIGLEN (sizeof(int) * SIGLENINT)

#define SIGLENBIT (SIGLEN * BITBYTE - 1) /* see makesign */

typedef char BITVEC[SIGLEN];
typedef char* BITVECP;

#define LOOPBYTE for (i = 0; i < SIGLEN; i++)

#define GETBYTE(x, i) (*((BITVECP)(x) + (int)((i) / BITBYTE)))
#define GETBITBYTE(x, i) ((((char)(x)) >> (i)) & 0x01)
#define CLRBIT(x, i) GETBYTE(x, i) &= ~(0x01 << ((i) % BITBYTE))
#define SETBIT(x, i) GETBYTE(x, i) |= (0x01 << ((i) % BITBYTE))
#define GETBIT(x, i) ((GETBYTE(x, i) >> ((i) % BITBYTE)) & 0x01)

#define HASHVAL(val) (((unsigned int)(val)) % SIGLENBIT)
#define HASH(sign, val) SETBIT((sign), HASHVAL(val))

#define ARRKEY 0x01
#define SIGNKEY 0x02
#define ALLISTRUE 0x04

#define ISARRKEY(x) (((TRGM*)x)->flag & ARRKEY)
#define ISSIGNKEY(x) (((TRGM*)x)->flag & SIGNKEY)
#define ISALLTRUE(x) (((TRGM*)x)->flag & ALLISTRUE)

#define CALCGTSIZE(flag, len) \
    (TRGMHDRSIZE + (((flag)&ARRKEY) ? ((len) * sizeof(trgm)) : (((flag)&ALLISTRUE) ? 0 : SIGLEN)))
#define GETSIGN(x) ((BITVECP)((char*)x + TRGMHDRSIZE))
#define GETARR(x) ((trgm*)((char*)x + TRGMHDRSIZE))
#define ARRNELEM(x) ((VARSIZE(x) - TRGMHDRSIZE) / sizeof(trgm))

extern float4 trgm_limit;

TRGM* generate_trgm(char* str, int slen);
TRGM* generate_wildcard_trgm(const char* str, int slen);
float4 cnt_sml(TRGM* trg1, TRGM* trg2);
bool trgm_contained_by(TRGM* trg1, TRGM* trg2);

#endif /* __TRGM_H__ */
